package org.mobile.model.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.StringWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.security.SecureRandom;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.KeyManager;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;

import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;

/**
 * 网络工具类.
 * @author carver.gu
 * @since 1.0, Sep 12, 2009
 */
public final class WebUtil {

    private static final Logger LOG = Logger.getLogger(WebUtil.class);

    private static final String DEFAULT_CHARSET = "utf-8";
    private static final String METHOD_POST = "POST";
    private static final String METHOD_GET = "GET";

    /**
     * @author sbwkl
     */
    private static class DefaultTrustManager implements X509TrustManager {
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }

        public void checkClientTrusted(X509Certificate[] chain,
                String authType) throws CertificateException {
        }

        public void checkServerTrusted(X509Certificate[] chain,
                String authType) throws CertificateException {
        }
    }

    private WebUtil() {
    }

    /**
     * 执行HTTP POST请求.
     * @param url
     *            请求地址
     * @param params
     *            请求参数
     * @param connectTimeout
     *            连接超时时间
     * @param readTimeout
     *            超时时间
     * @return 响应字符串
     * @throws IOException
     */
    public static String doPost(String url, Map<String, String> params,
            int connectTimeout, int readTimeout) throws IOException {
        return doPost(url, params, DEFAULT_CHARSET, connectTimeout,
                readTimeout);
    }

    /**
     * 执行HTTP POST请求.
     * @param url
     *            请求地址
     * @param params
     *            请求参数
     * @param charset
     *            字符集，如UTF-8, GBK, GB2312
     * @param connectTimeout
     *            连接超时时间
     * @param readTimeout
     *            超时时间
     * @return 响应字符串
     * @throws IOException
     */
    public static String doPost(String url, Map<String, String> params,
            String charset, int connectTimeout, int readTimeout)
            throws IOException {
        String ctype = "application/x-www-form-urlencoded;charset=" + charset;
        String query = buildQuery(params, charset);
        byte[] content = {};
        if(query != null) {
            content = query.getBytes(charset);
        }
        return doPost(url, ctype, content, connectTimeout, readTimeout);
    }

    /**
     * 执行HTTP POST请求.
     * @param url
     *            请求地址
     * @param ctype
     *            请求类型
     * @param content
     *            请求字节数组
     * @param connectTimeout
     *            连接超时时间
     * @param readTimeout
     *            超时时间
     * @return 响应字符串
     * @throws IOException
     */
    public static String doPost(String url, String ctype, byte[] content,
            int connectTimeout, int readTimeout) throws IOException {
        HttpURLConnection conn = null;
        OutputStream out = null;
        String rsp = null;
        try {
            conn = getConnection(new URL(url), METHOD_POST, ctype);
            conn.setConnectTimeout(connectTimeout);
            conn.setReadTimeout(readTimeout);
            out = conn.getOutputStream();
            out.write(content);
            rsp = getResponseAsString(conn);
        } catch(IOException e) {
            Map<String, String> map = getParamsFromUrl(url);
            LOG.error(conn + map.get("app_key") + map.get("method") + content);
            throw e;
        } finally {
            if(out != null) {
                out.close();
            }
            if(conn != null) {
                conn.disconnect();
            }
        }

        return rsp;
    }

    /**
     * 执行HTTP GET请求.
     * @param url
     *            请求地址
     * @param params
     *            请求参数
     * @return 响应字符串
     * @throws IOException
     */
    public static String doGet(String url, Map<String, String> params)
            throws IOException {
        return doGet(url, params, DEFAULT_CHARSET);
    }

    /**
     * 执行HTTP GET请求.
     * @param url
     *            请求地址
     * @param params
     *            请求参数
     * @param charset
     *            字符集，如UTF-8, GBK, GB2312
     * @return 响应字符串
     * @throws IOException
     */
    public static String doGet(String url, Map<String, String> params,
            String charset) throws IOException {
        HttpURLConnection conn = null;
        String rsp = null;

        try {
            String ctype = "application/x-www-form-urlencoded;charset="
                    + charset;
            String query = buildQuery(params, charset);
            try {
                conn = getConnection(buildGetUrl(url, query), METHOD_GET,
                        ctype);
            } catch(IOException e) {
                Map<String, String> map = getParamsFromUrl(url);
                LOG.error(conn + map.get("app_key") + map.get("method")
                        + params);
                throw e;
            }

            try {
                rsp = getResponseAsString(conn);
            } catch(IOException e) {
                Map<String, String> map = getParamsFromUrl(url);
                LOG.error(conn + map.get("app_key") + map.get("method")
                        + params);
                throw e;
            }

        } finally {
            if(conn != null) {
                conn.disconnect();
            }
        }

        return rsp;
    }

    private static HttpURLConnection getConnection(URL url, String method,
            String ctype) throws IOException {
        HttpURLConnection conn = null;
        if("https".equals(url.getProtocol())) {
            SSLContext ctx = null;
            try {
                ctx = SSLContext.getInstance("TLS");
                ctx.init(new KeyManager[0],
                        new TrustManager[] { new DefaultTrustManager() },
                        new SecureRandom());
            } catch(Exception e) {
                throw new IOException(e);
            }
            HttpsURLConnection connHttps = (HttpsURLConnection) url
                    .openConnection();
            connHttps.setSSLSocketFactory(ctx.getSocketFactory());
            connHttps.setHostnameVerifier(new HostnameVerifier() {
                public boolean verify(String hostname, SSLSession session) {
                    // 默认都认证通过
                    return true;
                }
            });
            conn = connHttps;
        } else {
            conn = (HttpURLConnection) url.openConnection();
        }

        conn.setRequestMethod(method);
        conn.setDoInput(true);
        conn.setDoOutput(true);
        conn.setRequestProperty("Accept",
                "text/xml,text/javascript,text/html");
        conn.setRequestProperty("User-Agent", "aop-sdk-java");
        conn.setRequestProperty("Content-Type", ctype);
        return conn;
    }

    private static URL buildGetUrl(String su, String query)
            throws IOException {
        String strUrl = su;
        URL url = new URL(strUrl);
        if(StringUtils.isEmpty(query)) {
            return url;
        }

        if(StringUtils.isEmpty(url.getQuery())) {
            if(strUrl.endsWith("?")) {
                strUrl = strUrl + query;
            } else {
                strUrl = strUrl + "?" + query;
            }
        } else {
            if(strUrl.endsWith("&")) {
                strUrl = strUrl + query;
            } else {
                strUrl = strUrl + "&" + query;
            }
        }

        return new URL(strUrl);
    }

    /**
     * @param params
     *            p
     * @param charset
     *            c
     * @return r
     * @throws IOException
     */
    public static String buildQuery(Map<String, String> params, String charset)
            throws IOException {
        if(params == null || params.isEmpty()) {
            return null;
        }

        StringBuilder query = new StringBuilder();
        Set<Entry<String, String>> entries = params.entrySet();
        boolean hasParam = false;

        for(Entry<String, String> entry : entries) {
            String name = entry.getKey();
            String value = entry.getValue();
            // 忽略参数名或参数值为空的参数
            if(StringUtils.isNotEmpty(name) && StringUtils.isNotEmpty(value)) {
                if(hasParam) {
                    query.append("&");
                } else {
                    hasParam = true;
                }

                query.append(name).append("=")
                        .append(URLEncoder.encode(value, charset));
            }
        }

        return query.toString();
    }

    protected static String getResponseAsString(HttpURLConnection conn)
            throws IOException {
        String charset = getResponseCharset(conn.getContentType());
        InputStream es = conn.getErrorStream();
        if(es == null) {
            return getStreamAsString(conn.getInputStream(), charset);
        } else {
            String msg = getStreamAsString(es, charset);
            if(StringUtils.isEmpty(msg)) {
                throw new IOException(conn.getResponseCode() + ":"
                        + conn.getResponseMessage());
            } else {
                throw new IOException(msg);
            }
        }
    }

    private static String getStreamAsString(InputStream stream, String charset)
            throws IOException {
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    stream, charset));
            StringWriter writer = new StringWriter();

            char[] chars = new char[256];
            int count = 0;
            while((count = reader.read(chars)) > 0) {
                writer.write(chars, 0, count);
            }

            return writer.toString();
        } finally {
            if(stream != null) {
                stream.close();
            }
        }
    }

    private static String getResponseCharset(String ctype) {
        String charset = DEFAULT_CHARSET;

        if(!StringUtils.isEmpty(ctype)) {
            String[] params = ctype.split(";");
            for(String param : params) {
                param = param.trim();
                if(param.startsWith("charset")) {
                    String[] pair = param.split("=", 2);
                    if(pair.length == 2) {
                        if(!StringUtils.isEmpty(pair[1])) {
                            charset = pair[1].trim();
                        }
                    }
                    break;
                }
            }
        }

        return charset;
    }

    /**
     * 使用默认的UTF-8字符集反编码请求参数值.
     * @param value
     *            参数值
     * @return 反编码后的参数值
     */
    public static String decode(String value) {
        return decode(value, DEFAULT_CHARSET);
    }

    /**
     * 使用默认的UTF-8字符集编码请求参数值.
     * @param value
     *            参数值
     * @return 编码后的参数值
     */
    public static String encode(String value) {
        return encode(value, DEFAULT_CHARSET);
    }

    /**
     * 使用指定的字符集反编码请求参数值.
     * @param value
     *            参数值
     * @param charset
     *            字符集
     * @return 反编码后的参数值
     */
    public static String decode(String value, String charset) {
        String result = null;
        if(!StringUtils.isEmpty(value)) {
            try {
                result = URLDecoder.decode(value, charset);
            } catch(IOException e) {
                throw new RuntimeException(e);
            }
        }
        return result;
    }

    /**
     * 使用指定的字符集编码请求参数值.
     * @param value
     *            参数值
     * @param charset
     *            字符集
     * @return 编码后的参数值
     */
    public static String encode(String value, String charset) {
        String result = null;
        if(!StringUtils.isEmpty(value)) {
            try {
                result = URLEncoder.encode(value, charset);
            } catch(IOException e) {
                throw new RuntimeException(e);
            }
        }
        return result;
    }

    private static Map<String, String> getParamsFromUrl(String url) {
        Map<String, String> map = null;
        if(url != null && url.indexOf('?') != -1) {
            map = splitUrlQuery(url.substring(url.indexOf('?') + 1));
        }
        if(map == null) {
            map = new HashMap<String, String>();
        }
        return map;
    }

    /**
     * 从URL中提取所有的参数.
     * @param query
     *            URL地址
     * @return 参数映射
     */
    public static Map<String, String> splitUrlQuery(String query) {
        Map<String, String> result = new HashMap<String, String>();

        String[] pairs = query.split("&");
        if(pairs != null && pairs.length > 0) {
            for(String pair : pairs) {
                String[] param = pair.split("=", 2);
                if(param != null && param.length == 2) {
                    result.put(param[0], param[1]);
                }
            }
        }

        return result;
    }

}
